1. Field of the Invention
The present invention relates to a retained roller assembly that is used under a system in which lubricant is supplied from outside and, more particularly, to a retained roller assembly for use in a roller bearing employed in various industrial machines and equipments.
2. Description of the Related Art
The retained roller assembly of the type referred to above has been well known, in which a plurality of needle rollers are accommodated within respective pockets, defined in a cylindrical roller retainer in a fashion spaced an equal distance in a direction circumferentially of the roller retainer, and in which the retainer has pairs of inner and outer roller holders defined therein, each pair being defined in respective opposite side faces of the corresponding pocket while the inner and outer roller holder of each pair are positioned on outer and inner diametric sides of the roller retainer. (See, for example, the Patent Document 1 listed below.) According to the Patent Document 1, the outer roller holders on the outer diametric side and the inner roller holders on the inner diametric side are disposed at respective positions differing from each other in a direction axially of the roller retainer so that a lubricant oil can flow into each of the pockets through between the neighboring roller holders to thereby increase a lubricating function.
The retainer needle roller assembly provided with roller holders on outer and inner diametric sides of circumferentially opposed side faces of each of the pockets is suggested in, for example, the Patent Document 2 listed below. According to the Patent Document 2, an axially intermediate portion and opposite ends of the side faces of each of the pockets are provided with cutouts with each of the rollers positioned between the opposite ends and the cutout at the intermediate portion and, at the same time, a circumferentially extending groove is provided at a portion of an outer diametric surface of the retainer corresponding to the cutouts at the intermediate portion to thereby increase the lubricating function.    [Patent Document 1] JP Laid-open Patent Publication No. H07-293569    [Patent Document 2] JP Laid-open Patent Publication No. H07-103240